@kaia >is there a Linux that looks like Windows?
No, kernels have no visual interface.

There are a bunch of DE's available for systemd/Linux that can be tweaked to look like windows or already do.

I suggest KDE, or Mate, or xfce4 and just call it "windows" and put the windows backgrounds on and he won't notice a difference.

He's better off not surrendering his freedom to such proprietary tax software, but WINE will probably run it and supports .desktop files, so you can put the same logo on the desktop and in the launch menu and have it run at a click.